A fine circuit pattern is produced on a surface of a semiconductor wafer or liquid crystal glass substrate by a photolithography process and an etching process. In the photolithography process, a chemical liquid supplying apparatus has been used to apply chemical liquid such as photoresist liquid to a surface of a wafer or glass substrate, and the chemical liquid accommodated in a container is sucked up by a pump, passes through a filter or the like, and is applied to an object to be applied such as a wafer from a nozzle. Japanese Patent Application Laid-Open Publication No. 2000-12449 (Patent Document 1) describes a treatment liquid supplying apparatus for supplying photoresist liquid to a wafer, and Japanese Patent Application Laid-Open Publication No. 2004-50026 (Patent Document 2) describes an application apparatus for supplying photoresist liquid to a liquid crystal glass substrate.
In such a chemical liquid supplying apparatus, if particles such as dust and dirt enter into the chemical liquid to be applied, they adhere to the object to be applied, whereby any pattern defects are caused and a yield of products is reduced. If the chemical liquid in a container is accumulated in a pump, it changes in quality. Therefore, since the chemical liquid changed in quality may become particles in some cases, the pump for discharging the chemical liquid is demanded not to be accumulated.
A pump in which a pump chamber supplying the chemical liquid and a drive chamber expanding/contracting the pump chamber are partitioned by an elastically deformable diaphragm or a partition film such as a tube is used as a pump for discharging the chemical liquid. The drive chamber is filled with indirect liquid, namely, an incompressible medium so as to pressurize the chemical liquid through the partition film. A pressurizing system of the incompressible medium includes a bellows type as described in Japanese Patent Application Laid-Open No. 10-61558 (Patent Document 3) and a syringe type of using a piston as disclosed in U.S. Pat. No. 5,167,837 (Patent Document 4).
A reciprocating pump for discharging liquefied gas includes, as described in Japanese Patent Application Laid-Open Publication No. 2006-144741 (Patent Document 5), a type of using a bellows to seal fluid in a piston from the outside.